密闭箱处理蛋鸡粪的氧化亚氮氨气排放研究

采用密切箱处理蛋鸡粪的方法，研究了密闭箱内产生的氧化亚氮、氨气的排放规律、影响因子及两者存在的内在联系。结果表明，氧化亚氮的产生与有机质的含量以及蛋鸡粪内部的氧氧状况密切相关；氨气与氧化亚氮的逐日排放变化规律存在很大的相似性；蛋鸡粪的内部温度作用表现不明显，受外界气温影响很小。     

规模奶牛养殖室外运动场春季温室气体与氨气排放特性

舍外运动场是中国传统奶牛养殖场的组成部分,同时也是温室气体和氨气(NH_3)的重要排放源。由于开放式生产设施污染气体排放的监测难度大,目前中国还普遍缺少奶牛运动场温室气体和NH_3排放通量的直接监测数据。该试验采用梯度法对北京地区春季典型开放式奶牛运动场的甲烷(CH_4)、氧化亚氮(N_2O)、二氧化碳(CO_2)等温室气体和NH_3浓度及其排放通量进行了监测分析,讨论了排放特征和关键影响因素,为获取中国北方地区奶牛运动场温室气体和NH_3的排放通量提供了基础数据支撑。测试运动场饲养了52头荷斯坦奶牛,年均单产约8 t,头均占地面积为20.77 m~2。结果表明,该奶牛运动场春季CH_4、N_2O和CO_2的排放通量为155.59、3.60和4 869.37 mg/(m~2·h),分别占温室气体排放总量的42.79%、9.37%和47.83%;NH_3的排放通量为66.27 mg/(m~2·h);排放峰值一般出现在运动场清粪之后。环境温度与CH_4、N_2O和NH_3排放量呈显著的正相关关系(P0.05),同时风速在一定范围内会促进CH_4、N_2O和NH_3的排放。奶牛场清粪活动不仅会加快污染气体的排放通量,还会影响温度和风速对气体排放通量的作用效果。     

猪舍氨气排放预测模型的研究现状

该文就氨气对环境的影响和猪舍氨气排放机制进行了简要的叙述，详细综述了氨气排放的机理模型和基于不同因素建立的经验模型。从中可以看出，国外对氨气排放的模型做了大量的研究，也取得了一定的研究成果，但是不同的研究结果有一定的差异。最后针对我国的实际情况，对我国氨气排放需进一步研究的问题进行了探讨。     

猪舍氨气排放预测模型的研究现状

该文就氨气对环境的影响和猪舍氨气排放机制进行了简要的叙述,详细综述了氨气排放的机理模型和基于不同因素建立的经验模型。从中可以看出,国外对氨气排放的模型做了大量的研究,也取得了一定的研究成果,但是不同的研究结果有一定的差异。最后针对中国的实际情况,对中国氨气排放需进一步研究的问题进行了探讨。     

不同土壤通风装置下肥料中氨气排放的评价

转齿型通风装置可提高肥料向土壤的渗透率,有效地减少氨气的排放和保存作物有效氮。分别在通风装置前后采用presidedress nitrate(NO3)tests法(以下简称PSNT法)测量通风角度在0°和10°时氨气的排放,并监测玉米作物产量。为测定N反应曲线和估量N等量肥的应用,以5个点矿质N肥制做曲线。用动态室方法测量NH3的累积排放,表明通风角度10°时比土表施用减少NH3排放量65%-75%。在2009年,在工具有角度安装时NH3排放有所减少,两个角度通风装置后加肥料带的处理比其它处理均显著提高了产量。从多重矿质N应用率与N响应曲线的产量关系表明作物产量要大于肥料应用期望值。     

静态箱法测定旱地农田温室气体时密闭时间的研究

应用自动观测装置对华北平原冬小麦田典型天气条件下密闭箱内气体排放通量进行了连续测定,分析了不同气体排放通量的变化过程,研究了密闭时间对其产生的影响.结果表明：测定CO2的密闭时间应不超过25min,测定N2O的密闭时间以15～30min为宜,测定CH4的密闭时间应在30min以内.此结果对静态箱法测定农田温室气体具有重要的参考价值.     

基于可调谐吸收光谱的畜禽舍氨气浓度检测

为开发一种基于可调谐吸收光谱（Tunable Diode Laser Absorption Spectroscopy,TDLAS）技术的畜禽舍NH3浓度实时在线监测装置,以满足畜禽舍环境监测与控制的需要。该研究基于TDLAS技术,采用气室式封闭光程,搭建了一套畜禽舍NH3浓度检测系统。该系统采用波长为1 512 nm蝶形激光器作为光源,根据分子吸收光谱理论,采用波长调制技术,实现了对畜禽舍NH3浓度检测。为优化检测系统性能,通过改变锯齿扫描信号、调制正弦信号的幅值与频率以及输入信号与参考信号相位差,确定了系统最佳的调制参数,并通过系统优化试验确定了系统最佳的气室加热温度、系统响应时间与二次谐波平均次数等关键参数。最后,通过浓度标定试验与性能试验对检测系统进行了测试。试验结果表明,检测系统调制参数在正弦调制信号频率为9 kHz、正弦调制信号幅值为30 mV、锯齿扫描信号频率为1 Hz、锯齿扫描范围为170～215 mV、谐波分析中输入信号与参考信号相位差为50°参数下对应的二次谐波形状与幅值最佳;不同浓度NH3与二次谐波幅值之间具有良好的线性关系（拟合方程相关系数r=0.995 8）;检测系统的进气响应时间约为42 s（气室自充气达到目标浓度99%）;气室加热温度为403 K时,NH3在气室吸附作用最小;Allan方差分析表明,检测系统在积分时间为10 s时达到探测限,探测限为0.038 mg/m3。在最优系统参数下对系统进行性能试验,得到检测系统综合线性误差为1.00%,定量测量综合重复误差为0.51％,可满足畜禽舍内NH3浓度长期持续监测的需求。     

牛粪堆肥方式对温室气体和氨气排放的影响

为明确堆肥过程中温室气体和氨气排放规律以及产生的总温室效应,在云南省大理州开展堆肥试验,并以奶牛粪便为试验材料,研究了农民堆肥(FC)、覆盖堆肥(CC)、覆盖-翻堆堆肥(CTC)和覆盖通风-翻堆堆肥(CATC)4种堆肥方式对温室气体和氨气排放的影响。结果表明:覆盖通风-翻堆堆肥(CATC)可提高堆肥腐熟度,有效降低CH4和N_2O排放,但并没降低CO2和NH_3排放;与农民堆肥(FC)相比,覆盖堆肥(CC)的CH4排放量增加了48.7%,而N2_O和NH3排放量与农民堆肥(FC)基本一致;覆盖-翻堆堆肥(CTC)虽然提高了腐熟度,但CH_4、CO_2和NH_3排放量较大;堆肥结束时,4个处理的总温室效应分别为25.6、32.9、38.1及18.0 kg/t;温度与CH_4、CO_2、N_2O和NH_3排放速率均极显著相关,pH值显著影响N_2O和NH_3的排放。因此,覆盖通风-翻堆堆肥(CATC)不仅能够满足堆肥产品的腐熟度要求,而且能够减少总温室效应,再加上其操作简便,能够在生产中推广应用。     

妊娠猪舍氨气及氧化亚氮浓度测定与排放通量的估算

在北京选择一典型猪场,对不同季节妊娠舍的氨气及氧化亚氮浓度进行了为期1年的试验测定,并根据二氧化碳平衡原理,对猪场不同生长阶段的妊娠猪含氮气体的排放通量进行了估算。结果表明:冬季2004年11月氨气和氧化亚氮的平均浓度分别为(11．64±4．36),(1．17±0．2)mg／m~3,夏季7月舍内氨气和氧化亚氮的平均浓度分别为(3．31±2．67),(0．6±0．02)mg／m~3;妊娠猪饲养期间的氨气排放通量为每头(185．2～500．8)mg／h,氧化亚氮为(3．85～35．93)mg／h。     

妊娠猪舍氨气及氧化亚氮浓度测定与排放通量的估算

在北京选择一典型猪场，对不同季节妊娠舍的氨气及氧化亚氮浓度进行了为期1年的试验测定，并根据二氧化碳平衡原理，对猪场不同生长阶段的妊娠猪含氮气体的排放通量进行了估算。结果表明：冬季2004年11月氨气和氧化亚氮的平均浓度分别为11.64±4.36，（1.17±0.2）mg／m³，夏季7月舍内氨气和氧化亚氮的平均浓度分别为3.31±2.67，（0.6±0.02）mg／m³；妊娠猪饲养期间的氨气排放通量为每头（185.2～500.8）mg／h，氧化亚氮为（3.85～35.93）mg／h。     

Gaseous emissions and soil fertility of homegardens in the Nuba Mountains,Sudan

Intensification of homegardens in the Nuba Mountains may lead to increases in C and nutrient losses from these small‐scale land‐use systems and potentially threaten their sustainability. This study, therefore, aimed at determining gaseous C and N fluxes from homegarden soils of different soil moisture, temperature, and C and N status. Emissions of CO₂, NH₃, and N₂O from soils of two traditional and two intensified homegardens and an uncultivated control were recorded bi‐weekly during the rainy season in 2010. Flux rates were determined with a portable dynamic closed chamber system consisting of a photo‐acoustic multi‐gas field monitor connected to a PTFE coated chamber. Topsoil moisture and temperature were recorded simultaneously to the gas measurements. Across all homegardens emissions averaged 4,527 kg CO₂‐C ha^?1, 22 kg NH₃‐N ha^?1, and 11 kg N₂O‐N ha^?1 for the observation period from June to December. Flux rates were largely positively correlated with soil moisture and predominantly negatively with soil temperature. Significant positive, but weak (r_s < 0.34) correlations between increasing management intensity and emissions were noted for CO₂‐C. Similarly, morning emissions of NH₃ and increasing management intensity were weakly correlated (r_s = 0.17). The relatively high gaseous C and N losses in the studied homegardens call for effective management practices to secure the soil organic C status of these traditional land‐use systems.     

A simple and easy method to measure ammonia volatilization: Accuracy under field conditions

Field studies on soil ammonia(NH₃)volatilization are restricted in many countries owing to the high costs commonly demanded for accurate quantification.We assessed the accuracy of a simple,open chamber design to capture NH₃under field conditions,as affected by different chamber placement schemes.Urea-15 N was surface applied to lysimeters installed in the spaces between maize rows.Open chambers made from plastic bottles were installed on each lysimeter with variations in i)N rates(3,8,13,and 18 g m^-2),ii)the height of the chamber above the soil surface(0,5,and 10 mm),and iii)chamber relocation(static vs.dynamic).Reference lysimeters without chambers were used to measure NH₃losses by¹⁵N-balance.Losses of NH₃-N accounted for more than 50%of the applied N.Relocation of the chambers had no impact on their NH₃-trapping efficiencies,proving to be an unnecessary procedure.Variation in the height of the chambers above the soil surface affected the capture of NH₃,but the results still maintained high linearity with the NH₃losses quantified by the reference method(R²>0.98).When the same placement scheme used in the introductory study describing the chamber was utilized(static and touching the soil surface),we found a trapping efficiency of 60%,which was very similar to that(57%)obtained in the previous study.Our results show that this simple,open chamber design can be used with satisfactory accuracy under field conditions,provided that simple,standardized procedures are warranted.     

A simple process-based model for estimating ammonia emissions from agricultural land after fertilizer applications

Abstract. Fertilizer applications to agricultural land are a significant source of ammonia (NH₃) emission to the atmosphere, accounting for approximately 10% of the total emissions from agriculture. Current estimates of emissions from fertilizer applications use 'fixed' emission factors. This paper describes a model in which the emission factors are expressed as a function of the important influencing variables: fertilizer type, soil pH, land use, application rate, rainfall and temperature. Total emission in 2002 for the UK were estimated by running the model for a 'standard UK' scenario, viz. 28.7 kt NH₃-N, which compares well with the UK inventory estimate of 30.4 kt NH₃-N. Differences exist in the estimates for specific fertilizer types, with the mean emission factor for urea applications to grassland, in particular, being lower by use of this model (13% compared with 23% of applied N for the UK inventory). Emission estimates were most sensitive to temperature and fertilizer type. Scenario testing showed that significant reductions in emission could be achieved by replacing urea with other forms of N fertilizer, by combining urea use with a urease inhibitor, or by modifying some management practices.     

Nitrous oxide emissions from arable soils in Germany — An evaluation of six long‐term field experiments

In this study emissions of N₂O from arable soils are summarized using data from long‐term N₂O monitoring experiments. The field experiments were conducted at six sites in Germany between 1992 and 1997. The annual N‐application rate ranged from 0 to 350 kg N ha^—1. Mineral and organic N‐fertilizer applications were temporarily split adapted to the growth stage of each crop. N‐fertilizer input and N‐yield by the crops were used to calculate the In/Out‐balance. The closed chamber technique was applied to monitor the N₂O fluxes from soil into the atmosphere. If possible, plants were included in the covers. Annual N₂O emission values were based on flux rate measurements of an entire year. The annual N₂O losses ranged from 0.53 to 16.78 kg N₂O‐N ha^—1 with higher N₂O emissions from organically fertilized plots as compared to minerally fertilized plots. Approximately 50% of the total annual emissions occurred during winter. No significant relationship between annual N₂O emissions and the respective N‐fertilization rate was found. This was attributed to site‐ and crop‐specific effects on N₂O emission. The calculation of the N₂O emission per unit N‐yield from winter cereal plots indicates that the site effect on N₂O emission is more important than the effect of N‐fertilization. From unfertilized soils at the sites Braunschweig and Timmerlah a N‐yield of 60.0 kg N ha^—1 a^—1 and N₂O emissions of 2 kg N ha^—1 a^—1 were measured. This high background emission was assigned to the amount and turnover of soil organic matter. For a crop rotation at the sites Braunschweig and Timmerlah the N In/Out‐balance over a period of four years was identified as a suitable predictor of N₂O emissions. This parameter characterizes the efficiency of N‐fertilization for crop production and allows for N‐mineralization from the soil.     

覆盖材料和厚度对堆存牛粪氨气和温室气体排放的影响

为了研究锯末和稻草2种材料覆盖以及不同厚度的锯末覆盖对牛粪堆存过程中氨气(NH3)和温室气体(N2O、CH4和CO2)排放量的影响,采用静态箱的方法测试了不同覆盖厚度(1、3和5 cm)和2种材料(锯末和稻草)覆盖下牛粪NH3、N2O、CH4和CO2排放量。结果表明,在不同厚度锯末覆盖的试验中,与不覆盖处理组相比,覆盖降低了牛粪NH3和CO2累积排放量,但覆盖显著增加了牛粪N2O和CH4累积排放量(P0.05);3个覆盖处理组内,NH3、N2O和CO2排放量随着覆盖厚度的增加而下降,然而,CH4排放量随着覆盖厚度的增加而升高;1、3和5 cm厚锯末覆盖的牛粪总温室气体排放量分别为108.61、103.57和101.36 g/kg,与1 cm锯末覆盖相比,3和5 cm厚锯末覆盖的牛粪总温室气体排放量显著降低(P0.05)。在相同质量的锯末(2 cm厚)和稻草(6 cm厚)2种材料覆盖的比较试验中,2种材料覆盖都显著降低了牛粪NH3和CO2的累积排放量(P0.05),但同时也显著增加了CH4的累积排放量(P0.05);锯末覆盖增加了牛粪N2O累积排放量(P0.05),而稻草覆盖则降低了牛粪N2O累积排放量(P0.05)。与锯末覆盖相比,稻草覆盖显著增加了CH4的累积排放量(P0.05),但同时显著降低了牛粪CO2的累积排放量(P0.05);锯末覆盖和稻草覆盖牛粪总温室气体排放量分别为101.51和109.46 g/kg,与锯末覆盖相比,稻草覆盖显著增加了牛粪总的温室气体排放量。试验结果表明,较厚的锯末(3和5 cm)覆盖对牛粪NH3和温室气体的减排效果更好。     

冬季堆肥中翻堆和覆盖对温室气体和氨气排放的影响

为明确冬季条垛堆肥过程中温室气体排放规律和主要影响因素,以猪粪和玉米秸秆为原料,研究了冬季条垛式堆肥过程中翻堆和覆盖作用对温室气体和氨气排放的影响。试验结果表明,在冬季堆肥高温期能维持2周以上,达到良好的卫生化效果;而在腐熟期堆体温度迅速下降,微生物活性停滞,堆肥腐熟进程受抑制。初始总有机碳的0.14%～0.76%以CH4损失,NH3和N2O的挥发则分别占到了初始总氮的10.3%～29.5%和0.81%～3.93%。数据分析结果显示,翻堆能够显著减少堆肥化过程中N2O和CH4排放,但增加NH3的排放。覆盖能够减少NH3的挥发,增加甲烷的排放,对N2O排放的影响不显著。     

Gaseous emissions of nitrogen and carbon from urban vegetable gardens in Bobo‐Dioulasso,Burkina Faso

Urban and peri‐urban agriculture (UPA) is an important livelihood strategy for the urban poor in sub‐Saharan Africa and contributes to meeting increasing food demands in the rapidly growing cities. Although in recent years many research activities have been geared towards enhancing the productivity of this land‐use system, little is known about turnover processes and nutrient efficiency of UPA. The aim of our study therefore was to determine horizontal fluxes of N, P, K, and C as well as gaseous N and C emissions in urban vegetable gardens of Bobo‐Dioulasso, Burkina Faso. Two gardens referred to as “Kodéni” and “Kuinima” were selected as representative for urban and peri‐urban systems classified as: (1) “commercial gardening + field crops and livestock system” and (2) “commercial gardening and semicommercial field crop system”, respectively. A nutrient‐balance approach was used to monitor matter fluxes from March 2008 to March 2009 in both gardens. Ammonia (NH₃), nitrous oxide (N₂O) and carbon dioxide (CO₂) emissions from the respective soils were measured during the coolest and the hottest period of the day using a closed‐chamber system. Annual partial balances amounted to 2056 kg N ha^–1, 615 kg P ha^–1, 1864 kg K ha^–1, and 33 893 kg C ha^–1 at Kodéni and to 1752 kg N ha^–1, 446 kg P ha^–1, 1643 kg K ha^–1, and 21 021 kg C ha^–1 at Kuinima. Emission rates were highest during the hot midday hours with peaks after fertilizer applications when fluxes of up to 1140 g NH₃‐N ha^–1 h^–1, 154 g N₂O‐N ha^–1 h^–1, 12 993 g CO₂‐C ha^–1 h^–1 were recorded for Kodéni and Kuinima. Estimated annual gaseous N (NH₃‐N + N₂O‐N) and C (CO₂‐C + CH₄‐C) losses reached 419 kg N ha^–1 and 35 862 kg C ha^–1 at Kodéni and 347 kg N ha^–1 and 22 364 kg C ha^–1 at Kuinima. For both gardens, this represented 20% and 106% of the N and C surpluses, respectively. Emissions of NH₃, largely emitted after surface application of manure and mineral fertilizers, accounted for 73% and 77% of total estimated N losses for Kodéni and Kuinima. To mitigate N losses nutrient‐management practices in UPA vegetable production of Bobo‐Dioulasso would greatly benefit from better synchronizing nutrient‐input rates with crop demands.     

A volatile discourse – reviewing aspects of ammonia emissions,models and atmospheric concentrations in The Netherlands

In the Netherlands, there is a vigorous debate on ammonia emissions, atmospheric concentrations and deposition between stakeholders and research institutions. In this article, we scrutinise some aspects of the ammonia discourse. In particular, we want to improve the understanding of the methodology for handling experimentally determined ammonia emissions. We show that uncertainty in published results is substantial. This uncertainty is under‐ or even unreported, and as a result, data in national emission inventories are overconfident by a wide margin. Next, we demonstrate that the statistical handling of data on atmospheric ammonia concentrations to produce national yearly atmospheric averages is oversimplified and consequently atmospheric concentrations are substantially overestimated. Finally, we show that the much‐discussed ‘ammonia gap’ – either the discrepancy between calculated and measured atmospheric ammonia concentrations or the difference observed between estimated NH₃ emission levels and those indicated by atmospheric measurements – is an expression of the widespread overconfidence placed in atmospheric modelling.